Interactions between cells, such as cell-cell recognition, adhesion, and alignment, depend upon highly organized, genetically programmed and timed associations of molecules recessed within the cell surface membrane or exposed at the membrane outer or inner surfaces. Abnormal interactions between malignant cells and host effector mechanisms may result from compositional and/or structural abnormalities in the molecules that comprise this dynamic internal and external membrane architecture. Computer-facilitated analyses of one and two dimensional IEF/SDS electrophoresis gels are used to quantitate and characterize the proteins and glycoproteins of normal and transformed cell membranes. HPLC and mass spectrometric analyses identify changes that occur in monoclonal antibody immunoprecipitated membrane molecules in response to the treatment of cells with chemical and physical carcinogens, cocarcinogens, modulators, lyphokines, and other immunobilogical effectors. These studies have demonstrated that the lymphokine, lymphotoxin, stimulates the synthesis of high MW membrane glycoproteins in normal hamster embryo cells and simultaneously prevents them from becoming malignantly transformed. Conversely, lymphotoxin decreases synthesis of high MW glycoproteins in malignantly transformed hamster cells and inhibits their growth.